Identification of multicollinearity and it’s effect in model selection

Multicollinearity is the problem experienced by the statisticians while at the time of evaluating a regression model. This paper explored the relationship between the sample variance inflation factor (vif) and F-ratio, based on this we proposed an exact F-test for the identification of multicollinearity and it overcomes the traditional procedures of rule of thumb. The authors critically identified that the variance inflation factor not only inflates the variance of the estimated regression coefficient and it also inflates the residual error variance of a given fitted regression model in various inflation level. Moreover, we also found a link between the problem of multicollinearity and its impact on the model selection decision. For this, the authors proposed multicollinearity corrected version of generalized information criteria which incorporates the effect of multicollinearity and help the statisticians to select a best model among the various competing models. This procedure numerically illustrated by fitting 12 different types of stepwise regression models based on 44 independent variables in a BSQ (Bank service Quality) study. Finally. Simulation study shows the transition in model selection after the correction of multicollinearity effect

Design, synthesis and activation of ruthenium arene anticancer complexes

The synthesis and characterisation of RuII complexes of the form [(η6-arene)Ru(N,N')X]+ (where N,N' is a bidentate chelating ligand and X is a halogen) are described; including the X-ray crystal structures of four of these complexes. The hydrolysis rates at 310 K of the complexes vary over many orders of magnitude and in some cases are followed by partial arene loss. Density Functional Theory (DFT) calculations suggest that the aquation mechanism occurs via a more associative pathway. The significant cytotoxic activity towards A2780 human ovarian cancer cells of some of the complexes is found to be dependent on the chelating ligand. Selective binding to 9-ethylguanine (9-EtG) but not to 9- ethyladenine (9-EtA) is observed in aqueous solution at 310 K in all cases. The X-ray crystal structure of a RuII arene 9-EtG adduct is also described. DFT calculations show that the 9- EtG nucleobase adducts of all complexes are thermodynamically preferred compared to those of 9-EtA. Preliminary CT-DNA studies in cell-free media suggest that some of these complexes can interact with DNA. A family of piano-stool RuII arene complexes of the form [(η6-arene)Ru(N,N')(L)]2+ (where N,N' is a chelating ligand and L is a pyridine or a pyridine-derivative), that can selectively photodissociate the monodentate ligand (L) when excited with UVA or visible light is described. The X-ray crystal structures of five of these complexes are also discussed. Their photoactivation allows the formation of a reactive aqua species that otherwise would not form in the dark. Results from TD-DFT calculations suggest that all the RuII pyridine complexes follow a relatively similar L-ligand photodissociation mechanism, likely to occur from a series of 3MC triplet states. It is shown how light activation can be used to phototrigger binding of these complexes to nucleobases with specific preference towards 9- EtG over 9-EtA. CT-DNA studies suggest that photoirradiated complexes interact with DNA via a combined coordinative, intercalative, and monofunctional binding mode. Some of the complexes are also cytotoxic against A2780 human ovarian cancer cell line in the absence of irradiation. The possibility of photo(triggering) hydride-transfer reactions using RuII arene complexes, NAD+, and formate as the hydride source under biologically relevant conditions is shown. The reactions occur either upon the spontaneous hydrolysis of a Ru–Cl bond in complexes of the form [(η6-arene)Ru(N,N')Cl]+ (where N,N' is a bidentate chelating ligand) or upon the photolysis of a Ru–N(Py) bond in [(η6-arene)Ru(N,N')Py]2+ (Py is pyridine). A mechanism involving the formation of a stable formate adduct followed by a hydrogen β- elimination is proposed. It is also demonstrated how a hydride-transfer from 1,4-NADH to some RuII arene chlorido complexes can occur in aqueous solution. Neutral RuII arene complexes of the form [(η6-arene)Ru(NH3)Cl2] which are constitutional analogues of cisplatin were synthesised by a novel synthetic method. These analogues display extensive H-bond interactions in the solid state as shown by X-ray crystal structures determination and their biexponential hydrolysis rates at 310 K vary over many orders of magnitude. The complexes are found to readily form mono- and di-guanine adducts upon hydrolysis but are not cytotoxic against the A2780 human ovarian cancer cell line up to the maximum concentration tested (100 μM).EThOS - Electronic Theses Online ServiceEuropean Union (EU)University of WarwickOverseas Research Students Awards Scheme (ORSAS)Consejo Nacional de Ciencia y Tecnología (Mexico) (CONACYT)GBUnited Kingdo

Effect of the thickness on the photocatalytic and the photocurrent properties of ZnO films deposited by spray pyrolysis

In this work, we have investigated the structure, morphology, photoluminescence, photocatalytic and photocurrent properties of ZnO thin films as a function of their film thickness (tZnO) fabricated via ultrasonic spray pyrolysis technique. The X-Ray diffraction patterns exhibited the formation of polycrystalline wurtzite phase of ZnO. Scanning electron microscopy images showed the uniform morphology with nanorod structure. The photosensitivity and photocatalytic efficiency are found to be optimum at tZnO = 1200 nm and are attributed to the improved photogeneration of charge carriers and higher concentration of oxygen vacancies. A direct correlation is established between the photosensitivity and photodegradation process. The incident photon-to-electron conversion efficiency (IPCE) and photocatalytic efficiency for the ZnO film at tZnO = 1200 nm are estimated to be 31.5% and 100% respectively. The obtained result suggests that ZnO thin films are potential candidates for applications in various optoelectronic devices.This study has been partially supported by Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/FIS/04650/2020 (JPBS) and DST SERB Project ECR/2017/002537(K.K.). Author KVA acknowledges DST, Govt. of India for the Inspire fellowship (IF170601)

Estimasi Suhu Permukaan Tanah Menggunakan Metode Algoritma Mono Window di Kabupaten Lamongan

Perubahan alih fungsi lahan merupakan salah satu fenomena yang banyak terjadi pada kabupaten yang berpotensi untuk pengembangan wilayah tersebut, salah satu area yang berpotensi untuk menjadi Kawasan Ekonomi Kreatif adalah Kabupaten Lamongan. Penelitian ini bertujuan untuk estimasi perubahan suhu permukaan tanah di Kabupaten Lamongan dengan memanfaatkan citra satelit Landsat 9. Citra satelit Landsat 9 diolah berdasarkan algoritma suhu untuk estimasi perhitungan suhu. Satelit Landsat 9 diluncurkan pada tahun 2021 dan merupakan satelit pengganti dari satelit Landsat 8. Satelit Landsat 9 memiliki 9 (Sembilan) band spectral dan 2 (dua) band termal. Pengolahan estimasi suhu permukaan tanah menggunakan band 4, band 5, dan band 10. Algoritma suhu permukaan tanah yang digunakan adaalah algoritma mono window. Dilakukan proses mosaic pada path 118 raw 65 dan path 119 raw 65. Hasil penelitian menunjukkan bahwa wilayah Kabupaten Lamongan memiliki tingkat kehijauan dengan rentang nilai -0,611 sampai 0,5 yang didominasi oleh tingkat kerapatan sedang. Hasil estimasi suhu permukaan tanah di Kabupaten Lamongan didominasi oleh suhu dengan rentang 23°C – 26°C dengan suhu tertinggi 29°C – 33°C. Kata kunci: Citra, Landsat 9, Suhu permukaan tana

Identifikasi Kekeringan Lahan Berdasarkan Citra Satelit

Kekeringan lahan merupakan salah satu permasalahan masyarakat pada musim kemarau. Menurut Badan Metereologi, Klimatologi, dan Geofisika memprediksi bahwa 58% wilayah zona musim (ZOM) Indonesia akan terlampat memasuki musim kemarau tahun 2021. Salah satu kabupaten yang mengalami kekeringan adalah Kabupaten Lamongan. Penelitian ini bertujuan untuk mengidentifikasi area kekeringan di Kabupaten Lamongan agar dampak kekeringan dampak diminimalisir. Metode identifikasi yang digunakan berdasarkan pengolahan data penginderaan jauh, yaitu memanfaatkan citra satelit Landsat 8. Citra Landsat 8 diolah berdasarkan algoritma kekeringan untuk mengidentifikasi area kekeringan. Luaran yang ditargetkan dalam penelitian ini adalah produk berupa peta kekeringan lahan dan materi sebagai bahan ajar pendukung perkuliahan. Adapun Tingkat Kematangan Teknologi (TKT) yang terdapat dalam penelitian ini terletak pada tingkat TKT 3, yaitu pembuktian konsep (proof of concept) dari algoritma yang telah ada dan diaplikasika pada studi kasus. Kata kunci: Identifikasi, Kekeringa

On using the distribution of Cook-Weisberg statistic and identification of influential observations

This paper proposed the distribution of Cook-Weisberg statistic used toevaluate the inuential observations in linear multiple regression analysis.The authors explored the relationship between the CW statistic and COVratio (Co-variance ratio) in terms of two independent F-ratio's and they showthe derived density function of the measure in a series expression form. More-over, the rst two moments of the distribution are derived in terms of Beta,di-gamma, poly-gamma functions, upper control limit of CW-statistic is alsoestablished and the authors computed the critical points of CW-statistic at5% and 1% signicance level for dierent sample sizes and varying no.ofpredictors. Finally, the numerical example shows the identication of the influential observations and the results extracted from the proposed approachesare more scientic, systematic and it's exactness outperforms the traditionalapproach

Synthesis, charecterization and antibiological activities of N'-(2-Hydroxyphenyl)-N'- (4-Methylpiperazin-1-YL) Furan-2-Carbohydrazide

Present study deals with synthesis of novel Mannich bases from N'-(2-HYDROXY PHENYL)-N'-(4-METHYLPIPERAZIN-1-YL) FURAN-2-CARBOHYDRAZIDE instead of formaldehyde, other aliphatic or aromatic aldehydes or ketones can be employed. The amine used may be ammonia or 1o or 2o aliphatic amine. Mostly diethyl amine is preferred to use. The newly synthesized compounds were characterized by elemental analysis for IR, electronic absorption spectra, TLC. All the synthesized compounds were tested for their antibacterial activities against Gram positive and Gram negative bacteria, antimicrobial activities and antifungal activitie

Initial and long term stability of augmented knee arthroplasty using finite element methods

EThOS - Electronic Theses Online ServiceGBUnited Kingdo